Originally posted by KGEG
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Germanwings A320 on BCN-DUS flight crash near Nice, France
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Thanks. So it doesn't result in a phugoid (long period longitudinal oscillation).
I guess if you had changing winds as you descended (or changed pilot speed selection) it could possibly look a bit like it?
With the A/P engaged the aircraft will pitch to maintain a speed (either pilot selected or FMS generated), and so if you descend down a few thousand feet and see an increase in headwind, the aircraft would pitch to reduce speed, have a reduction in rate of descent, then increase again once the speed had been reached.
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Originally posted by Gabriel View PostOn the contrary, I think that any reasonable pre-impact break-up process would leave a wide scatter areas, yes, but with some big chunks (Re: Lockerbie). The miniature debris that we can see there talks of some high energy and violent impact.
But just seeing such debris speaks volumes of the impact it had, and the altitude numbers that have been published make it a case of no wonder it turned into such tiny pieces.
But that is why it got me wondering for a second, that the debris was in different crevices but it obviously settled back down into those.
Edit: Or it crashed farther up the mountain and the debris fell down the side of it a bit, the crevices acting like river channels directing them different ways.
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Originally posted by Gabriel View PostThanks. So it doesn't result in a phugoid (long period longitudinal oscillation).
I hadn't considered structural damage to the crew 02 lines. That could also fit.
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Originally posted by Rapha477 View Post"Open des" or "expedite" mode, according to vertical speed values and changes, I believe more in expedite mode, after a while. The oldest 320s don't maintain the speed perfectly and it's usual to encounter such speed variations in open des or exp mode, open clb...(exp desc it's +/- VMO/MMO if I remember well)
It's consistent in my opinion with depressurization and I believe in a question of hypoxia for the pilots (or the pilot if the other one left his seat for some reasons).
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According to french weekly newspaper Le Point, all Germanwings 320s are ACARS equiped. That could explain why Lufhtansa claimed early that "it's an accident, and all others scenarios are pure speculation".
http://www.lepoint.fr
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Originally posted by Leftseat86 View PostIf it turns out the pilot's oxygen system was compromised rendering them incapacitated, but that of the passengers and cabin crew was working, would the locked cockpit door prevent anyone in the cabin from rendering aid to the pilots or delivering them oxygen / attempting to wake them up?
Details of how the system works are not public (thankfully), but the pilots can actively block the access in response to an attempt to enter with the code.
Incapacited pilots = no active blocking by the pilots = access with the code is granted.
--- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
--- Defend what you say with arguments, not by imposing your credentials ---
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What do I think ?
Disregarding for now any terrorist input, which I doubt on such a flight......
My poor, simple, non pilot brain adds up phugoid oscillation during a faster than usual but not excessively fast descent + 8 minutes to descend + no mayday call + an Airbus trying to fly itself when the human element fails + a locked cockpit door, which isn't really a factor as unconsciousness would prevail on both sides of the door....
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Decompression incident. That's where my money is going.If it 'ain't broken........ Don't try to mend it !
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Originally posted by brianw999 View PostWhat do I think ?
Disregarding for now any terrorist input, which I doubt on such a flight......
My poor, simple, non pilot brain adds up phugoid oscillation during a faster than usual but not excessively fast descent + 8 minutes to descend + no mayday call + an Airbus trying to fly itself when the human element fails + a locked cockpit door, which isn't really a factor as unconsciousness would prevail on both sides of the door....
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Decompression incident. That's where my money is going.
I don't buy the phugoid. The Airbus will not phugoid in any AP mode and even with the AP off (except in direct law), due to it's "G on stick" control law.
Now, I saw no evidence of phugoid so far. But hypoxia scenario fits well:
- Sudden decompression.
- Pilots fail to don O2 mask or O2 system fails.
- But they manage to start an emergency descent in "open des" (basically, they select open des and retard the throttles).
- Pilots loss consciousness.
- At the last minute, after descending well below the mid-tens, the pilots start to wake up (but perhaps they are still partially impaired).
-This explains the level-off / pull up (rumor) in the last minute.
Still pure speculation, but of fine quality.
--- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
--- Defend what you say with arguments, not by imposing your credentials ---
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Going with decompression - could the age and hours of the airframe be relevant?
I was surprised that LH/GW were operating 24 year old aircraft in such an intensive and time dependent low cost operation with 20/25 minute turnrounds. I note their rivals EasyJet & Ryanair fleet average age are both kept around the 5/6 year mark or better. (i'll be flying in an EJ A320 in a couple of weeks to Spain!)
Why the different methodolgy?
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This explains the level-off / pull up (rumor) in the last minute.
This is - Turn (spin) the altitude selector down, and pull (for Open descent)
Turn the heading selector (if desired) and pull (for heading)
Pull for selected airspeed.
This gets the descent initiated. The pilot then would check the FMA's, ensure thrust is coming to idle, extend speed brakes, and then go back to the modes and accurately set a desired altitude, heading, and decide if they wanted to descend at the current speed (i.e. potential structural damage) or accelerate to reduce descent time (e.g. dual pack failure).
If the pilot became incapacitated after doing the first three items, but before returning to the mode panel, the aircraft would descend to whatever altitude ended up in the altitude window after the first turn (which is basically a blind spin of the knob). The pilot would not need to wake up for the aircraft to level off at the random level obtained.
Did it climb? I guess we'll find that out, but it could be speculation based on incorrect altitude data (such as that obtained by difference between QNH and Standard altimeter). A climb would certainly need to be pilot initiated.
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